Abstract P055

King Faisal Specialist Hospital and Research Centre

Introduction: The incorporation of radiotherapy (RT) into the initial treatment protocols for classical Hodgkin lymphoma (cHL) may vary across different medical institutions. Our study focuses on the outcomes of pts with classic Hodgkin lymphoma treated at three tertiary care centers in the Middle East. The retrospective analysis of collected data aims to uncover any differences between pts who underwent RT and those who did not.

Pts and methods: Our retrospective analysis involved reviewing the medical records of pts with early-stage cHL treated between 2010 and 2021. Our analysis assessed the rates of CR and relapse.

Results: Total of 490 pts (247 female 243 males) with median age of 27 years fulfilled the inclusion criteria. Mean Follow-up time is 59 months. Most pts had nodular sclerosis subtype (68.2%) and 87.8% had stage II with 64.9% having B symptoms. In total, 57.8% of pts received RT. At the end of treatment, 87.8% of the entire cohort achieved complete remission. 46 pts of entire group relapsed: 21 pts did not receive RT, while 25 pts received RT as consolidation. Among the pts who reached CR at first-line chemotherapy (n=420), 57% proceeded with RT. Relapse rate of pts in CR who received RT as consolidation was 7.5%, compared to 7.2% (p=0.9) for those who did not receive RT and reached CR at end of first-line chemotherapy. A positive interim PET scan was documented in 25.7% of entire patient population, with 23.8% of these pts still having active disease at the end of chemotherapy. Among pts with positive interim and end-of-treatment (EOT) PET scan, 66.7% received RT, and 30% of these developed relapsed/refractory (r/r) disease. Additionally, 57.9% of pts with positive interim PET scan received RT, while 42.1% did not. Among those who did not receive RT, 15% had r/r disease, compared to 17.8% of those who did receive RT (p=0.8). Ten pts with positive interim PET scan had negative EOT-PET scans and therefore did not receive RT. Among these pts, the rate of r/r disease was high, at 60%. At data cut-off (11/2022) there was no significant difference in PFS rate (p = 0.75) between pts who underwent radiation in comparison with the group of pts who were not irradiated. Overall survival was similar.

Conclusion: While our real-world data doesn't favor routine consolidation with RT for early-stage cHL pts with negative EOT-PET, our findings highlight RT's effectiveness in curing a substantial percentage of individuals with positive interim and EOT-PET.